the thing i like to see, and then we even have 1 more solution for the button is "the second click"
so now we have:

"short click" show dashboard
"long click" show menu

i would like to add:

"second (short) click" show desktop (or what ever)

and the second click just looks what is now visible, and if the dashboard is there (which is the short "first" click) then it will execute the second click

this way you can very vast toggle between stuff.
then i would have dashboard and desktop as the first and second click..